Vanessa ate 2 slices of cake. Kevin ate 3 slices. If Vanessa ate $\dfrac{2}{10}$ of the cake, what fraction of the cake is remaining?
Solution: If 2 slices represent $\dfrac{2}{10}$ of the cake, there must have been a total of 10 slices. $\text{fraction of cake remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 5 slices, which leaves 5 out of 10 slices remaining. There is $\dfrac{5}{10}$ of the cake remaining.